Figure 4

Analysis of differential transcription between adult and juvenile earthworms. Panel A presents a Principal Component Analysis of transcript profiles from adult and juvenile earthworms. The array data used for this analysis were normalised using per chip and per gene median polishing, and data from poor quantity spots were removed; no additional filtering was performed. Panel B displays hierarchical clustering (using a distance algorithm for both conditions and genes) for genes showing significant (p < 0.01) differential expression using a t-test with Benjamini and Hochberg False Discovery. Juvenile data are represented as yellow spheres and adult data are shown as triangles (red indicate those organisms sampled in November and green for those harvested in December).